Diaphragm



l4 1931i? J. HILFERS 1,800,449

I DIAPHRAGM Filed Jan. 22, 1929 INVENTOR WITNESSES I170; fill era A ORNEY Patented Apr. 14, 1931 PATENT OFFICE JOHN HILFERS, OF NEW YORK, N. Y.

DIAPHRAGM Application filed January 22, 1929. Serial No. 334,334.

This invention relates to diaphragms and more particularly to sound reproducing vibrating diaphragms.

An object of the invention is to provide a 51 non-metallic diaphragm composed of a thin veneer of wood or other suitable non-metallic material having a covering thereon of aluminum leaf.

A diaphragm of this character with the aluminum leaf thereon constituting a fixed part thereof gives materially improved results in sound reproduction. The aluminum leaf neutralizes the vibrations or sound reproduction so that there is no taint of metalhe sound vibration. The diaphragm will produce each and every tone faithfully without any undertones or overtones and will eliminate tinpannysounds such as are reproduced by diaphragms now in the reproduction of piano music.

IVhile I preferably employ a thin veneer of wood in which the aluminum leaf is permanently fixed, I do not wish to be limited to wood as it is well within the scope of my invention to employ other non-metallic materials such as fiber, paper or fabric.

In a more specific sense the invention includes a sheet of non-metallic material such as wood, etc., to which aluminum leaf is caused to adhere through the medium of water glass as an adhesive, and the diaphragm as a whole is coated with a celluloid varnish.

The diaphragm may of course be shaped in any way desired, may be of any suitable size and may be adapted for use in connection with sound boxes for reproduction from phonographic records, or the diaphragm might be used in connection with a loud speaker for radio or for any other use where sound reproduction is had through the me dium ofa vibrating diaphragm.

With these and other objects in view, the invention consists in certain novel features of construction and combinations and arrangements of parts which will be more fully hereinafter described and pointed out in the claims.

In the accompanying drawings.

Figure l is a view in elevation, the several 59 surfaces or thicknesses of material being broken away to indicate other thicknesses back of the same;

Figure 2 is a grossly exaggerated view in section on the line 22 of Figure 1;

Figure 3 is a still more exaggerated fragmentary view in longitudinal section illustrating the various thicknesses of materials.

My improved diaphragm includes a sheet or thickness 1 of wood or any other suitable non-metallic material, although I believe that wood is decidedly preferable. To one face of the wood an aluminum leaf 2 is secured, and as a securing means I preferably employ water glass 3, and the entire diaphragm is coated preferably with an aluminum varnish 4.

The diaphragm is preferably of circular disk type, given any desired shape for rigidity and proper distribution of the variations throughout and, as above stated, has a wide range "of usefulness in connection with the reproduction of sound.

The drawings, in so far as the thicknesses of the water glass, the varnish and the leaf are concerned, are grossly exaggerated for in actual appearance neither the water glass, the varnish nor the leaf will have any observable thickness.

The parts are assembled with the water glass between the aluminum leaf and the wood or other material, and then pressed or shaped while damp or shaped in any other manner, and the finished product is coated with the varnish.

While I have illustrated and described what I believe to be a preferred embodiment of my invention it is obvious various slight changes and alterations might be made in the general form of the parts described without departing from my invention and hence I do not limit myself to the precise details set forth but consider myself at liberty to make such changes and alterations as fairly fall within the spirit and scope of the appended claims. 95

I claim:

1. As a new article of manufacture, a diaphragm of the character stated, composed of non-metallic material having aluminum leaf on one face thereof, said aluminum leaf and W January, A. D. 1929.

non-metallic material secured together by water glass.

2. As a new article of manufacture, a diaphragm of the character stated, composed of non-metallic material having aluminum leaf on oneface thereof, said aluminum leaf and non-metallic material secured to ether .by water glass, and a coating of varnlsh enclosing the diaphragm and constituting a part thereof.

3. As a new article of manufacture, a sound reproducing diaphragm, composed of thicknesses of thin wood veneer and aluminum leaf secured together.

Signed at New York, in the county of New York and State of New York this 19th day of JOHN HILFERSV; 

